Watch This Polar Bear Use a Stone to Shatter Its Zoo Enclosure

Zoos are designed to give visitors a glimpse at some of the planet's most majestic a fearsome creatures, viewed from a safe distance and from behind protective barriers. But in a recent incident, caught on film at a facility in the Netherlands, that sense of security (among other things) was quite unexpectedly shattered. In a YouTube clip provided by Dutch news source Diergaarde Blijdorp , a polar bear at the Rotterdam Zoo can be observed carrying a large stone from the bottom of its enclosure and heaving it against the glass walls of the tank. For the two men seen talking in the video, their close proximately to that iconic arctic predator doesn't seem to sink in until the animal's rock-tossing efforts finally make a breakthrough, causing the glass to fracture. Officials say that the polar bear had only broken the first of five layers of glass, yet that was clearly enough...